1. Field of the Invention
The present invention relates generally to mounting apparatuses, and more particularly to a mounting assembly for readily mounting a heat sink onto a heat-generating component such as a Central Processing Unit (CPU).
2. Prior Art
With the continuing development of computer electronics technology, new electronic packages such as the latest CPUs can perform more and more functions. Heat generated by these modern electronic packages has increased commensurately. Therefore, bigger and heavier heat sinks are becoming increasingly necessary to efficiently remove the heat from the electronic packages.
A conventional heat sink assembly is disclosed in U.S. Pat. No. 5,464,054. In this kind of heat sink assembly, a clip made from a single metal wire is positioned in a groove of a heat sink for mounting the heat sink to an electronic package. Two resilient arms extend from opposite ends of the clip in directions substantially perpendicular to each other. A distal end of each arm is bent to form a hook engaging in a corresponding receiver formed on a frame or socket that holds the electronic package, thereby fastening the heat sink to the electronic package. However, selecting a wire clip with an appropriate diameter can be problematic. If the wire is too thin, the clip cannot provide a sufficient spring force to hold the heat sink, and the heat sink is prone to be displaced when the assembly is subjected to vibration or shock. If the wire is too thick, an unduly large force is required to engage the clip into the corresponding receivers. Additionally, a tool is generally required for installation or removal of the clip, which makes these processes excessively time consuming. Furthermore, the tool is liable to slip during use, which can cause damage to other components adjacent the electronic package. All these difficulties reduce the efficiency of assembly in mass production facilities. Reduced efficiency is translated into increased costs.
FIG. 11 shows a retaining clip for cooperating with a socket to fasten a heat sink to a heat-generating device such as a CPU. The retaining clip comprises a pressing body 1. A first leg 11 extends from an end of the pressing body 1, for engaging with a first ear formed on the socket. An operation lever 2 is pivotably mounted to an opposite end of the pressing body 1 by a first mounting shaft 71. A second leg 2 is pivotably mounted to an end of the operation lever 2 that is near the pressing body 1 by a second mounting shaft 72, for engaging with a second ear formed on the socket. When the operation lever 2 is rotated to a locked position in which the operation lever 2 abuts the pressing body, the second leg 2 is driven upwardly to engage with the second ear of the socket, thereby enabling the pressing body to exert an urging force pressing the heat sink toward the CPU.
During operation, the urging force of the pressing body 1 is a result of an overall deformation of the retaining clip caused by rotation of the operation lever 2. However, the retaining clip is usually configured such that the operation lever 2 can be only stably maintained in a fixed position, that is the locked position, to enable the press body 1 to urge the heat sink to the CPU. Therefore, rotation of the operation lever 2 can only cause a very limited range of deformations of the retaining clip, which provides a very limited range of urging forces. The retaining clip thus generally can be hardly applied to heat sinks having different specifications.
In addition, the operation lever 2 is usually configured to have a considerable length for ease of operation. A large operation space is required. This militates the trend of electrical products becoming smaller and smaller.